Abstract
The phase opposition of velocity waveforms between coronary arteries (predominantly diastolic) and veins (systolic) is the most prominent characteristic of coronary hemodynamics. The phase opposition indicates the importance of intramyocardial capacitance vessels, as a determinant of phasic coronary arterial and venous flows. To investigate the functional characteristics of the intramyocardial capacitance vessels and its physiological significance, we analyzed the change in venous flow following changes in coronary arterial inflow. It was shown that during diastole the intramyocardial capacitance vessels have two functional components, unstressed volume and ordinary capacitance. Unstressed volume is defined as the volume of blood in a vessel at zero transmural pressure, and it was ~5% of the volume of the myocardium. The systolic coronary venous outflow showed a significant, positive correlation with the total displaceable blood volume stored in the intramyocardial unstressed volume and ordinary capacitance. When the unstressed volume was saturated, the coronary inflow was decreased significantly, compared with that for the unsaturated condition. Thus, the increase in intramyocardial blood volume decreases the coronary arterial inflow, whereas it enhances coronary venous outflow. The latter is an interesting analogy to the Starling's law of the heart.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
